Added default to get_encryption_type to hide warning when building

src/main.ino

@@ -396,6 +396,8 @@ String get_encryption_type(wifi_auth_mode_t encryptionType) {
             return "WPA_WPA2_PSK";
         case (WIFI_AUTH_WPA2_ENTERPRISE):
             return "WPA2_ENTERPRISE";
+        default:
+            return "Unknown";
     }
 }